IB/core: Add flow control to the portmapper netlink calls

During connection establishment with a large number of
connections, it is possible that the connection requests
might fail. Adding flow control prevents this failure.
Change ibnl_unicast to use blocking to enable flow control.

Signed-off-by: Mustafa Ismail <[e-mail]>
Signed-off-by: Faisal Latif <[e-mail]>
Signed-off-by: Shiraz Saleem <[e-mail]>
Signed-off-by: Doug Ledford <[e-mail]>

drivers/infiniband/core/netlink.c

···
 int ibnl_unicast(struct sk_buff *skb, struct nlmsghdr *nlh,
 			__u32 pid)
 {
-	return nlmsg_unicast(nls, skb, pid);
+	int err;
+
+	err = netlink_unicast(nls, skb, pid, 0);
+	return (err < 0) ? err : 0;
 }
 EXPORT_SYMBOL(ibnl_unicast);
 
···
 		return -ENOMEM;
 	}
 
+	nls->sk_sndtimeo = 10 * HZ;
 	return 0;
 }